Xylylene based polyether membranes for gas separation

Abstract

The invention relates to novel xylylene based polyether gas separation membranes and a method of separating gases using such membranes.

What is claimed is: 
     
       1. A semi-permeable gas separation membrane comprising a thin discriminating region of a xylylene based polyether polymer possessing a backbone structure corresponding to the formula: ##STR4## wherein R is individually in each occurrence a hydrogen radical, a monovalent C 1-12  hydrocarbyl radical, a C 1-12  halohydrocarbyl radical, and a halogen, Ar 1 , Ar 2 , Ar 3 , and Ar 4  are individually in each occurrence a divalent aromatic residue selected from the group consisting of: A. an unsubstituted or inertly substituted phenylene, or an unsubstituted or inertly substituted naphthylene;   B. a bisphenylene of the formula: ##STR5##  wherein L is individually in each occurrence selected from the group consisting of a direct bond, a divalent C 1-15  hydrocarbyl radical, a divalent C 1-8  halohydrocarbyl radical, --O--, --CO--, --S--, --SO 2  --, and --SS--, X is individually in each occurrence selected from the group consisting of a hydrogen radical, a monovalent C 1-4  hydrocarbyl radical, a C 1-4  halohydrocarbyl radical, and a halogen, and   m is individually in each occurrence a positive integer between 1 and 4 inclusive; and     C. a divalent bisphenyl fluorenyl or spiro indanyl radical;     w is a positive integer between 0 and 3 inclusive;   x is a positive integer between 1 and about 500 inclusive,   y is a positive integer between 0 and about 500 inclusive, and   z is a positive integer between 0 and about 500 inclusive, wherein the ratio of ##EQU12##  is between about 0.002 and 1 inclusive; and n is a positive integer representing a degree of polymerization which provides a number-average molecular weight of at least about 3,000.   
     
     
       2. The membrane of claim 1 wherein at least one of Ar 1 , Ar 2 , Ar 3 , and Ar 4  comprise an inertly substituted phenylene or naphthylene, wherein the inert substituents are selected from the group consisting of a monovalent C 1-8  hydrocarbyl radical, a monovalent C 1-8  hydrocarbyloxy radical, and a halogen. 
     
     
       3. The membrane of claim 2 wherein the inert substituents are selected from the group consisting of a monovalent C 1-6  hydrocarbyl radical, a monovalent C 1-6  hydrocarbyloxy radical, and a halogen. 
     
     
       4. The membrane of claim 3 wherein the inert substituents are a halogen selected from the group consisting of fluorine, chlorine, and bromine. 
     
     
       5. The membrane of claim 1 wherein at least one of Ar 1 , Ar 2 , Ar 3 , and Ar 4  comprise a bisphenylene wherein L is selected from the group consisting of a direct bond, a divalent C 1-8  hydrocarbyl radical, a divalent C 1-4  halohydrocarbyl radical, --O--, --CO--, --S--, --SO--, --SO 2  --, and --SS--. 
     
     
       6. The membrane of claim 5 wherein L is selected from the group consisting of a direct bond, a divalent C 1-6  hydrocarbyl radical, a divalent C 1-6  halohydrocarbyl radical, --O--, --CO--, --S--, --SO--, --SO 2  --, and --SS--. 
     
     
       7. The membrane of claim 6 wherein L is selected from the group consisting of a direct bond, a divalent C 1-3  hydrocarbyl radical, and a divalent C 1-3  fluorohydrocarbyl radical. 
     
     
       8. The membrane of claim 1 wherein at least one of Ar 1 , Ar 2 , Ar 3 , and Ar 4  comprise a bisphenylene wherein X is selected from the group consisting of a hydrogen radical a monovalent C 1-6  hydrocarbyl radical, and a halogen. 
     
     
       9. The membrane of claim 8 wherein X is a halogen selected from the group consisting of bromine, chlorine, and fluorine. 
     
     
       10. The membrane of claim 1 wherein the membrane is composite or asymmetric. 
     
     
       11. The membrane of claim 1 wherein the membrane is a hollow fiber. 
     
     
       12. The membrane of claim 1 wherein the gas selectivity of oxygen/nitrogen at about 30° is at least about 5.0. 
     
     
       13. The membrane of claim 12 wherein the gas permeability for oxygen at about 30° C. is at least about 0.1 Barrer. 
     
     
       14. The membrane of claim 13 wherein the reduced gas flux for oxygen at about 30° C. is at least about ##EQU13## 
     
     
       15. The membrane of claim 1 wherein the gas selectivity of helium/methane at about 30° C. is at least about 50. 
     
     
       16. The membrane of claim 15 wherein the gas permeability for oxygen helium at about 30° C. is at least about 1.0 Barrer. 
     
     
       17. The membrane of claim 16 wherein the reduced gas flux for helium at about 30° C. is at least about ##EQU14## 
     
     
       18. A process of separating gases comprising: A. contacting one side of a semi-permeable gas separation membrane with a feed gas mixture under pressure, wherein the membrane divides a separation chamber into a high pressure side into which the feed gas mixture is fed and a low pressure side;   B. maintaining a pressure differential across the membrane under conditions such that at least one gaseous component in the feed gas mixture selectively permeates through the membrane from the high pressure side to the low pressure side of the membrane;   C. removing from the low pressure side of the membrane permeated gas which is enriched in at least one selectively permeating gaseous component; and   D. removing from the high pressure side of the membrane non-permeated gas which is depleted in at least one selectively permeating gaseous component; wherein the membrane comprises a thin discriminating region of a xylylene based polyether polymer possessing a backbone structure corresponding to the formula: ##STR6## wherein R is individually in each occurrence a hydrogen radical, a monovalent C 1-12  hydrocarbyl radical, a C 1-12  halohydrocarbyl radical, and a halogen,     Ar 1 , Ar 2 , Ar 3 , and Ar 4  are individually in each occurrence a divalent aromatic residue selected from the group consisting of: A. an unsubstituted or inertly substituted phenylene, or an unsubstituted or inertly substituted naphthylene;   B. a bisphenylene of the formula: ##STR7##  wherein L is individually in each occurrence selected from the group consisting of a direct bond, a divalent C 1-15  hydrocarbyl radical, a divalent C 1-8  halohydrocarbyl radical, --O--, --CO--, --S--, --SO 2  --, and --SS--, X is individually in each occurrence selected from the group consisting of a hydrogen radical, a monovalent C 1-4  hydrocarbyl radical,   a C 1-4  halohydrocarbyl radical, and a halogen, and   m is individually in each occurrence a positive integer between 1 and 4 inclusive; and     C. a divalent bisphenyl fluorenyl or spiro indanyl radical;     w is a positive integer between 0 and 3 inclusive;   x is a positive integer between 1 and about 500 inclusive,   y is a positive integer between 0 and about 500 inclusive, and   z is a positive integer between 0 and about 500 inclusive, wherein the ratio of ##EQU15##  is between about 0.002 and 1 inclusive; and n is a positive integer representing a degree of polymerization which provides a number-average molecular weight of at least about 3,000.   
     
     
       19. The process of claim 18 wherein the feed gas mixture contains at least one of the gases selected from the group consisting of hydrogen, helium, oxygen, nitrogen, carbon monoxide, carbon dioxide, water vapor, hydrogen sulfide, ammonia, and light hydrocarbons. 
     
     
       20. The process of claim 19 wherein the pressure of the feed gas mixture is between about 5 psig and about 1000 psig. 
     
     
       21. The process of claim 20 wherein the temperature of the feed gas mixture is between about -50° C. and about 50° C. 
     
     
       22. The process of claim 20 wherein the temperature of the membrane is between about -50° C. and about 50° C.